A tank belonging to the Saudi-led coalition is seen in the sand dunes of the Yemeni front line province of Marib September 14, 2015. Gulf Arab coalition forces fighting Houthi militia in Yemen are advancing on the capital in a two-pronged offensive, generals told reporters on Monday at a desert oil compound they have turned into a military base. Picture taken September 14, 2015. REUTERS/Noah Browning
A tank belonging to the Saudi-led coalition is seen in the sand dunes of the Yemeni front line province of Marib September 14, 2015. Gulf Arab coalition forces fighting Houthi militia in Yemen are advancing on the capital in a two-pronged offensive, generals told reporters on Monday at a desert oil compound they have turned into a military base.